Giant ramshorns do eat plants.. they especially like floaters, like frogbit. Still, an interesting snail and they do get to quite a size. I have one with a shell that's nearly white, with green marks on it, which look oddly similar to the colour of copper 'rust' though the bodies only come in three colours.. light brown [ or gold, if you like ] medium brown and a brown so dark it looks black. Most shells are either brown or gold with darker stripes, similar to the giant apple snail. They're part of the apple snail family. One thing I note about the shell of the Giant is that the shell's opening is flared a bit, and they have an operculum, which the small ramshorns do not. If your snail has an operculum, it may well be a Giant ramshorn. If there isn't an operculum, it's not.
The unusual light shelled guy [ or gal, I"m not sure] I have is nearly two inches in diameter and there's another one the same colour too, that's smaller. They lay very messy, underwater egg clutches. Big loose sacs of slimy jelly with quite big eggs in them, usually stuck to a stem or leaf. Similar to Spixi snail eggs, but Spixi eggs are smaller and the clutches are not nearly as messy or large. A snail fancier I know told me that if you keep Spixi and Giant ramshorns together you may get hybrids that are quite big and simply mow plants down. I keep them completely separate, just to make sure that doesn't happen. I have to confess, I'm getting tired of them munching the frogbit, so I will likely get them their own tank and give them plants that I don't care about too much.
The little ramshorns do not eat plants at all. They will clean leaves of anything they find on them, but never eat the leaves. I like the colours they come in.. red of course, but also light and dark blue, chocolate and even leopard, along with the wild form which is a mid to dark brown. Red and blue ones have nearly transparent shells that look white if the snail dies. I have a couple of red ones that are close to nickel sized, and I wonder how old they are, given they are much bigger than most I have seen.Their shells have become rather ridged looking, though I am not sure why this is happening and it doesn't seem to affect them at all.
o I can take care of him properly. Also need to figure which tank he needs to be in for his eventual adult size. I assume he is plant safe since he came with plants. 
